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Chloride‐depletion of photosynthetic water oxidase
Author(s) -
Lübbers Karin,
Drevenstedt Wolfgang,
Junge Wolfgang
Publication year - 1993
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(93)80825-f
Subject(s) - chemistry , photochemistry , proton , photosynthesis , chloride , thylakoid , flashing , excited state , flash (photography) , photosynthetic reaction centre , biophysics , chloroplast , biochemistry , biology , atomic physics , optics , physics , organic chemistry , quantum mechanics , gene
Chloride depletion blocks the normal four‐step progress of photosynthetic water oxidation. We studied proton release in chloride‐depleted thylakoids which were dark‐adapted and excited by flashing light. Proton release was blocked from the second flash on, possibly leaving an uncompensated positive charge in the catalytic centre. The reduction of P + 680 by Tyr z was still very rapid (⪡ 10 μs). From the third flash on, P + 680 was reduced more slowly ( ), and by an electrogenic back‐reaction. The uncompensated positive charge may be the reason why the rapid reduction of P + 680 by Tyr z is prevented and the transmembrane charge‐pair recombination is facilitated.